Phase change ink compositions comprising diurethanes as amorphous materials

ABSTRACT

A phase change ink composition comprising an amorphous component, a crystalline material, and optionally, a colorant, which are suitable for high speed ink jet printing, including printing on coated paper substrates. In embodiments, the amorphous component comprises a diurethane compound or derivatives thereof.

CROSS-REFERENCE TO RELATED APPLICATIONS

Reference is made to commonly owned and co-pending, U.S. patentapplication Ser. No. ______ (not yet assigned) entitled “Phase ChangeInk Compositions Comprising Crystalline Diurethanes And DerivativesThereof” to Naveen Chopra et al., electronically filed on the same dayherewith (Attorney Docket No. 20110356-396152); U.S. patent applicationSer. No. ______ (not yet assigned) entitled “Solid Ink CompositionsComprising Crystalline Sulfone Compounds and Derivatives Thereof” toKentaro Morimitsu et al., electronically filed on the same day herewith(Attorney Docket No. 20110561-396955); U.S. patent application Ser. No.______ (not yet assigned) entitled “Phase Change Inks ComprisingCrystalline Amides” to Kentaro Morimitsu et al., electronically filed onthe same day herewith (Attorney Docket No. 20110665-397243); U.S. patentapplication Ser. No. ______ (not yet assigned) entitled “Phase ChangeInk Compositions Comprising Aromatic Ethers” to Kentaro Morimitsu etal., electronically filed on the same day herewith (Attorney Docket No.20110362-396157); U.S. patent application Ser. No. ______ (not yetassigned) entitled “Fast Crystallizing Crystalline-Amorphous InkCompositions and Methods for Making the Same” to Gabriel Iftime et al.,electronically filed on the same day herewith (Attorney Docket No.20110459-399389); U.S. patent application Ser. No. ______ (not yetassigned) entitled “Rapid Solidifying Crystalline-Amorphous Inks” toGabriel Iftime et al., electronically filed on the same day herewith(Attorney Docket No. 20110982-399395); U.S. patent application Ser. No.______ (not yet assigned) entitled “Phase Change Inks ComprisingInorganic Nucleating Agents” to Daryl W. Vanbesien et al.,electronically filed on the same day herewith (Attorney Docket No.20111206-400896); U.S. patent application Ser. No. ______ (not yetassigned) entitled “Phase Change Inks Comprising Fatty Acids” to GabrielIftime et al., electronically filed on the same day herewith (AttorneyDocket No. 20110815-399390); U.S. patent application Ser. No. ______(not yet assigned) entitled “Phase Change Inks Comprising AromaticDiester Crystalline Compounds” to Kentaro Morimitsu et al.,electronically filed on the same day herewith (Attorney Docket No.20111040-399927); U.S. patent application Ser. No. ______ (not yetassigned) entitled “Phase Change Inks Comprising Organic Pigments” toJennifer Belelie et al., electronically filed on the same day herewith(Attorney Docket No. 20110418-399388); and U.S. patent application Ser.No. ______ (not yet assigned) entitled “TROM Process for Measuring theRate of Crystallization of Solid Inks” to Gabriel Iftime et al.,electronically filed on the same day herewith (Attorney Docket No.20110828-401275), and U.S. patent application Ser. No. ______ (not yetassigned) entitled “Rapidly Crystallizing Phase Change Inks and Methodsfor Forming the Same” to Jennifer Belelie et al., electronically filedon the same day herewith (Attorney Docket No. 20111455-403044); theentire disclosures of which are incorporated herein by reference in itsentirety.

BACKGROUND

The present embodiments relate to phase change ink compositionscharacterized by being solid at room temperature (e.g., 20-27° C.) andmolten at an elevated temperature at which the molten ink is applied toa substrate. These phase change ink compositions can be used for ink jetprinting. The present embodiments are directed to a novel phase changeink composition comprising an amorphous material, a crystallinematerial, and optionally a colorant, and methods of making the same. Theamorphous material comprises a diurethane compound and derivativesthereof.

Ink jet printing processes may employ inks that are solid at roomtemperature and liquid at elevated temperatures. Such inks may bereferred to as solid inks, hot melt inks, phase change inks and thelike. For example, U.S. Pat. No. 4,490,731, the disclosure of which istotally incorporated herein by reference, discloses an apparatus fordispensing phase change ink for printing on a recording medium such aspaper. In piezo ink jet printing processes employing hot melt inks, thephase change ink is melted by the heater in the printing apparatus andutilized (jetted) as a liquid in a manner similar to that ofconventional piezo ink jet printing. Upon contact with the printingrecording medium, the molten ink solidifies rapidly, enabling thecolorant to substantially remain on the surface of the recording mediuminstead of being carried into the recording medium (for example, paper)by capillary action, thereby enabling higher print density than isgenerally obtained with liquid inks. Advantages of a phase change ink inink jet printing are thus elimination of potential spillage of the inkduring handling, a wide range of print density and quality, minimalpaper cockle or distortion, and enablement of indefinite periods ofnonprinting without the danger of nozzle clogging, even without cappingthe nozzles.

In general, phase change inks (sometimes referred to as “hot melt inks”)are in the solid phase at ambient temperature, but exist in the liquidphase at the elevated operating temperature of an ink jet printingdevice. At the jetting temperature, droplets of liquid ink are ejectedfrom the printing device and, when the ink droplets contact the surfaceof the recording medium, either directly or via an intermediate heatedtransfer belt or drum, they quickly solidify to form a predeterminedpattern of solidified ink drops.

Phase change inks for color printing typically comprise a phase changeink carrier composition which is combined with a phase change inkcompatible colorant. In a specific embodiment, a series of colored phasechange inks can be formed by combining ink carrier compositions withcompatible subtractive primary colorants. The subtractive primarycolored phase change inks can comprise four component dyes or pigments,namely, cyan, magenta, yellow and black, although the inks are notlimited to these four colors. These subtractive primary colored inks canbe formed by using a single dye or pigment or a mixture of dyes orpigments. For example, magenta can be obtained by using a mixture ofSolvent Red Dyes or a composite black can be obtained by mixing severaldyes. U.S. Pat. No. 4,889,560, U.S. Pat. No. 4,889,761, and U.S. Pat.No. 5,372,852, the disclosures of each of which are totally incorporatedherein by reference, teach that the subtractive primary colorantsemployed can comprise dyes from the classes of Color Index (C.I.)Solvent Dyes, Disperse Dyes, modified Acid and Direct Dyes, and BasicDyes. The colorants can also include pigments, as disclosed in, forexample, U.S. Pat. No. 5,221,335, the disclosure of which is totallyincorporated herein by reference. U.S. Pat. No. 5,621,022, thedisclosure of which is totally incorporated herein by reference,discloses the use of a specific class of polymeric dyes in phase changeink compositions.

Phase change inks are desirable for ink jet printers because they remainin a solid phase at room temperature during shipping, long term storage,and the like. In addition, the problems associated with nozzle cloggingas a result of ink evaporation with liquid ink jet inks are largelyeliminated, thereby improving the reliability of the ink jet printing.Further, in phase change ink jet printers wherein the ink droplets areapplied directly onto the final recording medium (for example, paper,transparency material, and the like), the droplets solidify immediatelyupon contact with the recording medium, so that migration of ink alongthe printing medium is prevented and dot quality is improved.

While the above conventional phase change ink technology is successfulin producing vivid images and providing economy of jet use and substratelatitude on porous papers, such technology has not been satisfactory forcoated substrates. Thus, while known compositions and processes aresuitable for their intended purposes, a need remains for additionalmeans for forming images or printing on coated paper substrates. Assuch, there is a need to find alternative compositions for phase changeink compositions and future printing technologies to provide customerswith excellent image quality on all substrates, including selecting andidentifying different classes of materials that are suitable for use asdesirable ink components. There is a further need for printing theseinks at high speeds as required by digital presses in productionenvironment.

Each of the foregoing U.S. patents and patent publications areincorporated by reference herein. Further, the appropriate componentsand process aspects of the each of the foregoing U.S. patents and patentpublications may be selected for the present disclosure in embodimentsthereof.

SUMMARY

According to embodiments illustrated herein, there is provided novelphase change ink compositions comprising amorphous materials comprisingdiurethanes and derivatives thereof suitable for ink jet printing,including printing on coated paper substrates.

In particular, the present embodiments provide a phase change inkcomprising a crystalline compound; and an amorphous diurethane compoundhaving a formula of:

wherein Z is selected from the group consisting of

wherein each R₃ and R₄ is i) an alkyl group wherein the alkyl can belinear or branched having from about 1 to about 8 carbon atoms, or ii)an aryl group; with the proviso that when Z is —(CH₂)₆—, both R₃ and R₄are not —(CH₂)_(n)—C₆H₅ wherein n=0-4; wherein the phase change inkcrystallizes in less than 15 seconds.

In further embodiments, there is provided a phase change ink comprisingamorphous diurethane compound; and a crystalline compound; wherein theamorphous diurethane compound is synthesized from a diisocyanate and atleast one alcohol optionally in the presence of a catalyst.

In yet other embodiments, there is provided a phase change inkcomprising a crystalline compound; an amorphous diurethane compoundhaving a formula of:

wherein Z is selected from the group consisting of

wherein each R₃ and R₄ is i) an alkyl group wherein the alkyl can belinear or branched having from about 1 to about 8 carbon atoms, or ii)an aryl group; each R₃ and R₄ is independently selected from the groupconsisting of

with the proviso that when Z is —(CH₂)₆—, both R₃ and R₄ are not—(CH₂)_(n)—C₆H₆ wherein n=0-4.

BRIEF DESCRIPTION OF THE DRAWINGS

For a better understanding of the present embodiments, reference may behad to the accompanying figures.

FIG. 1 illustrates the TROM process showing images of crystallineformation in an ink base from crystallization onset to crystallizationcompletion according to an embodiment of the disclosure.

FIG. 2 is differential scanning calorimetry (DSC) data of(Abitol)₂1,6-hexamethylendiisocyanate [(Abitol)₂HDI] confirming theamorphous properties according to the present embodiments (the DSC datawas obtained on a Q1000 Differential Scanning calorimeter (TAInstruments) at a rate of 10° C./min from −50 to 150 to −50° C.);

FIG. 3 is a graph illustrating rheology data of (Abitol)₂HDI; and

FIG. 4 is a graph illustrating rheology data of an ink sample comprising(Abitol)₂HDI made according to the present embodiments.

All of the rheology measurements were made on a RFS3 Rheometer (TAinstruments), using a 25 mm parallel plate, at a frequency of 1 Hz; themethod used was a temperature sweep from high to low temperatures, intemperature steps of 5° C., a soak (equilibration) time of 120 secondsbetween each temperature and at a constant frequency of 1 Hz).

DETAILED DESCRIPTION

In the following description, it is understood that other embodimentsmay be utilized and structural and operational changes may be madewithout departure from the scope of the present embodiments disclosedherein.

Phase change ink technology broadens printing capability and customerbase across many markets, and the diversity of printing applicationswill be facilitated by effective integration of printhead technology,print process and ink materials. The phase change ink compositions arecharacterized by being solid at room temperature and molten at anelevated temperature at which the molten ink is applied to a substrate.As discussed above, while current ink options are successful for porouspaper substrates, these options are not always satisfactory for coatedpaper substrates.

It was previously discovered that using a mixture of crystalline andamorphous small molecule compounds in solid ink formulations providesrobust inks, and in particular, solid inks which demonstrate robustimages on coated paper. (U.S. patent application Ser. No. 13/095,636entitled “Solid Ink Compositions Comprising Crystalline-AmorphousMixtures” to Jennifer L. Belelie et al., (Attorney Docket No.20101286-390681) filed Apr. 27, 2011. Using this approach is surprising,however, due to the known properties of crystalline or amorphousmaterials. For crystalline materials, small molecules generally tend tocrystallize when solidifying and low molecular weight organic solids aregenerally crystals. While crystalline materials are generally harder andmore resistant, such materials are also much more brittle, so thatprinted matter made using a mainly crystalline ink composition is fairlysensitive to damage. For amorphous materials, high molecular weightamorphous materials, such as polymers, become viscous and sticky liquidsat high temperature, but do not show sufficiently low viscosity at hightemperatures. As a result, the polymers cannot be jetted from print headnozzles at desirable jetting temperature (≦140° C.). In the presentembodiments, however, it is discovered that a robust solid ink can beobtained through a blend of crystalline and amorphous compounds.

Print samples made with such phase change inks demonstrate betterrobustness with respect to scratch, fold, and fold offset as compared tocurrently available phase change inks.

However, the present inventors discovered that in many cases mixturesmade of crystalline and amorphous materials with optional dye colorantsolidify slowly when printed on substrates from a molten state. Suchslow solidifying inks are not suitable for high speed printingenvironments, like for example production printing, where printing atspeeds higher than 100 feet per minute is required. Solidification ofthe ink is due to crystallization of the crystalline component in theink when cooling.

The inventors have found that fast crystallization of a composition madeof a crystalline and an amorphous component is not an inherent propertyof the composition.

The present embodiments provide novel phase change ink compositionscomprising crystalline materials and amorphous diurethane materialswhich crystallize fast and are therefore suitable for high speed ink jetprinting, including printing on coated paper.

The present embodiments provide a new type of ink jet phase change inkcomposition which comprises a blend of (1) crystalline and (2) amorphouscomponents, generally in a weight ratio of from about 60:40 to about95:5, respectively. In more specific embodiments, the weight ratio ofthe crystalline to amorphous component is from about 65:35 to about95:5, or is from about 70:30 to about 90:10, or is from about 70:30 toabout 80:20. In other embodiments, the crystalline and amorphouscomponents are blended in a weight ratio of from about 1.5 to about 20or from about 2.0 to about 10, respectively. Each component impartsspecific properties to the phase change inks, and the blend of thecomponents provides inks that exhibit excellent robustness on uncoatedand coated substrates. The crystalline component in the ink formulationdrives the phase change through rapid crystallization on cooling. Thecrystalline component also sets up the structure of the final ink filmand creates a hard ink by reducing the tackiness of the amorphouscomponent. The amorphous components provide tackiness and impartrobustness to the printed ink.

The Amorphous Compound

The present embodiments comprise amorphous materials selected from thegroup of diurethane compounds and their derivatives, including lineardiurethanes. The amorphous diurethanes are synthesized through one-stepsolvent-free reactions using commercially available diisocyanates withalcohols. This solvent-free process is low cost, avoids any byproductsand has high reactor throughput. These amorphous materials have alsobeen found to demonstrate good phase transition as well as have specificthermal and rheological properties that make the materials suitable foruse in phase change inks. For example, the hydrogen bonding sites on theurethanes offer stronger intermolecular forces than other amorphousmaterials, for example, diesters, which results in an ink that providesremarkable robustness, with respect to scratch, fold, and fold offsetcompared to currently available commercial phase change inks on the samemedia.

These materials show relatively low viscosity (<10² centipoise (cps), orfrom about 1 to about 100 cps, or from about 5 to about 95 cps) near thejetting temperature (≦140° C., or from about 100 to about 140° C., orfrom about 105 to about 140° C.) but very high viscosity (>10⁵ cps) atroom temperature.

The low viscosity in the jetting range (100-140° C.) provides highformulation latitude. The high viscosity at room temperature impartsrobustness. These characteristics make the materials good candidates forthe amorphous component. Moreover, the diurethanes and their derivativesare synthesized from commercially available materials, thus, reducingthe costs of the phase change inks.

The amorphous diurethane of the present disclosure has the followingformula:

wherein Z is selected from the group consisting of:

and wherein Z can be attached to either side of the nitrogen atom of thediurethane formula through the bond labeled with *; each R₃ and R₄ is i)an alkyl group wherein the alkyl can be linear or branched having fromabout 1 to about 8 carbon atoms, or ii) an aryl group; with the provisothat when Z is —(CH₂)₆—, both R₃ and R₄ are not —(CH₂)_(n)—C₆H₅ whereinn=0-4. Each R₃ and R₄ can be any linear or branched alkyl includingmethyl, ethyl, propyl, (n-, iso-, sec- and t-) butyl, (n-, iso-, t- andthe like) pentyl, (n-, iso-, t- and the like) hexyl, (n-, iso-, t- andthe like) heptyl, or (n-, iso-, t- and the like) octyl.In certain embodiments, R₃ and R₄ is independently selected from thegroup consisting of:

with the proviso that when Z is —(CH₂)₆—, both R₃ and R₄ are not—(CH₂)_(n)—C₆H₆ wherein n=0-4.

In certain embodiments, z is —(CH₂)₆— and both R₃ and R₄ are

R₃ and R₄ can also be fused ring alcohols, hydroabietyl alcohol (e.g.rosin alcohols), isoborneol, and ethoxylated nonylphenol (such as IgepalCA210, from Rhodia).

The Crystalline Compound

In combination with the amorphous materials of the present embodiments,crystalline materials are also used.

Suitable crystalline components include those disclosed in U.S. patentapplication Ser. No. ______ to Chopra et al. (Attorney Docket No.20110356-396152), entitled “Phase Change Ink Compositions ComprisingDiurethanes and Derivatives Thereof,” which is hereby incorporated byreference in its entirety. These crystalline materials comprisediurethanes having a general formula:

wherein Q is alkanediyl; each R₆ and R₇ is independently phenyl orcyclohexyl optionally substituted with one or more alkyl; i is 0 or 1; jis 0 or 1; p is 1 to 4; q is 1 to 4. In certain of such embodiments,each R₆ and R₇ is independently phenyl or cyclohexyl optionallysubstituted with one or more methyl or ethyl. In certain of suchembodiments, R₆ and R₇ is phenyl.

In certain embodiments, Q is —(CH₂)_(n)— and n is 4 to 8. In certain ofsuch embodiments, n is 6.

Crystalline diurethane compounds can be synthesized by the generalscheme shown below:

wherein R is —(CH₂)_(p)—(O)_(i)—R₆, and R′ is —(CH₂)_(q)—(O)_(j)—R₇

Suitable alcohols (ROH or R′OH) for use in the disclosure include butnot limited to benzyl alcohol, 2-phenylethanol, 2-phenoxyethanol,3-phenylpropan-1-ol, hydrocinnamyl alcohol, cinnamyl alcohol,C₆H₅(CH₂)₄OH, cyclohexanol, 2-methylcyclohexanol, 3-methylcyclohexanol,4-methylcyclohexanol, cyclohexylmethanol; 2-methylcyclohexylmethanol,3-methylcyclohexylmethanol, 4-methylcyclohexylmethanol, and4-ethylcyclohexanol. Each ROH and R′OH is independently selected fromthe listed disclosed above.

Or, each R and R′ (or each R₆ and R₇) is independently selected frombenzyl, 2-phenylethyl, 2-phenoxyethyl, hydrocinnamyl, cinnamyl,C₆H₅(CH₂)₄—, cyclohexyl, 2-methylcyclohexyl, 3-phenylpropanyl,3-methylcyclohexyl, 4-methylcyclohexyl, cyclohexylmethyl,2-methylcyclohexylmethyl, 3-methylcyclohexylmethyl,4-methylcyclohexylmethyl, and 4-ethylcyclohexanyl.

The above reaction may be conducted by combining diisocyanate andalcohol in the melt in the presence of a tin catalyst, such as, dibutyltin dilaurate (Fascat 4202), dibutyl tin oxide (Fascat 4100); a zinccatalyst, such as Bi cat Z; or a bismuth catalyst, such as Bi cat 8124;Bi cat 8108. Only trace quantities of catalyst are required for theprocess. The relatively fast formation of diurethanes in a solvent-freeprocess represents a significant improvement over the previous synthesisof crystalline components. In addition, the solvent-free processeliminates problems with byproducts and also means higher reactorthroughput.

The crystalline materials show sharp crystallization, relatively lowviscosity (≦10¹ centipoise (cps), or from about 0.5 to about 20 cps, orfrom about 1 to about 15 cps) at a temperature of about 140° C., butvery high viscosity (>10⁶ cps) at room temperature. These materials havea melting temperature (T_(melt)) of less than 150° C., or from about 65to about 150° C., or from about 66 to about 145° C., and acrystallization temperature (T_(crys)) of greater than 60° C., or fromabout 60 to about 140° C., or from about 65 to about 120° C. The ΔTbetween T_(melt) and T_(crys) is less than about 55° C.

The crystalline and amorphous materials of the present embodiments werefound to be miscible with one another and the resulting ink compositionsformulated with the crystalline and amorphous materials show goodrheological profiles. Image samples created by the phase change inkcomposition on coated paper by K-proof exhibit excellent robustness. AK-proofer is a common test fixture in a print shop.

The present embodiments comprise a balance of amorphous and crystallinematerials to realize a sharp phase transition from liquid to solid andfacilitate hard and robust printed images, while maintaining a desiredlevel of viscosity. Prints made with this ink demonstrated advantagesover commercially available inks, such as for example, better robustnessagainst scratch. Thus, the present diurethane compounds and derivativesthereof, which provide amorphous components for the phase change inks,have been discovered to produce robust inks having desirable rheologicalprofiles and that meet the many requirements for inkjet printing.

In embodiments, the crystalline material is present an amount of fromabout 60 percent to about 95 percent by weight, or from about 65 percentto about 95 percent by weight, or from about 70 percent to about 90percent by weight of the total weight of the ink composition. Inembodiments, the amorphous material is present in an amount of fromabout 5 percent to about 40 percent by weight, or from about 5 percentto about 35 percent by weight, or from about 10 percent to about 30percent by weight of the total weight of the ink composition.

In embodiments, in the molten state, the resulting solid ink has aviscosity of from about 1 to about 22 cps, or from about 4 to about 15cps, or from about 6 to about 12 cps, at a the jetting temperature. Thejetting temperature is typically comprised in a range from about 100° C.to about 140° C. In embodiments, the solid ink has a viscosity of about>10⁶ cps, at room temperature. In embodiments, the solid ink has aT_(melt) of from about 65 to about 140° C., or from about 70 to about140° C., from about 80 to about 135° C. and a T_(crys) of from about 40to about 140° C., or from about 45 to about 130° C., from about 50 toabout 120° C., as determined by DSC at a rate of 10° C./min.

The present inventors have discovered specific diurethane compounds thatare meet the requirements for use as the amorphous material in phasechange ink compositions. The primary requirement for phase change ink isthat it is in the liquid state at jetting temperature (typically fromabout 100 to about 140° C.) and solid state at room temperature. Thesuitable diurethane candidates can be synthesized by the generalreaction scheme shown below:

wherein R is —(CH₂)_(p)—(O)_(i)—R₅, and R′ is —(CH₂)_(q)—(O)_(j)—R₆.

The above reaction was conducted by combining diisocyanate and alcoholin the melt in the presence of a tin catalyst, such as, dibutyl tindilaurate (Fascat 4202), dibutyl tin oxide (Fascat 4100); zinc catalystssuch as Bi cat Z; or bismuth catalysts such as Bi cat 8124; Bi cat 8108.Only trace quantities of catalyst are required for the process. Suitablediisocyanates such as 1,6-hexamethylenediisocyanate,isophoronediisocyanate, 1,3-bis(isocyanatomethyl)cyclohexane,m-tetramethyl xylylene diisocyanate, dicyclohexylmethane diisocyanateand 2,4,4-trimethylhexamethylene diisocyanate,(hexamethylene-1,6-diisocyanate (HDI); trimethylhexamethylenediisocyanate (TMHDI); 2,5-bis-isocyanatomethylene diisocyanate (BIMC),tetramethylxylene diisocyanate (TMXDI); isophorone diisocyanate (IPDI),diphenylmethane-4,4′-diisocyanate (MDI); hydrogenateddiphenylmethane-4,4′-diisocyanate (H₁₂MDI); phenylisocyanate; toluenediisocyanate (TDI), phenylene diisocyanate may be used. Variousdiisocyanates were used in the preparation of the amorphous diurethanes,including: 1,6-hexamethylenediisocyanate (HDI), isophoronediisocyanate(IPDI), 1,3-bis(isocyanatomethyl)cyclohexane (BIMC), m-tetramethylxylylene diisocyanate (TMXDI), dicyclohexylmethane diisocyanate (H12MDI)and 2,4,4-trimethylhexamethylene diisocyanate (TMHDI). Thesediisocyanates were chosen based on wide commercial availability and lowcost.

The relatively fast formation of diurethanes in a solvent-free processrepresents a significant improvement over the previous synthesis ofamorphous components. In addition, the solvent-free process eliminatesproblems with byproducts and also means higher reactor throughput. Ascan be seen, the nature of the endgroup alcohol impacts the Tg andviscosity properties of the resulting urethane formed. It is believedthat function-hydrogen-bonding sites on the urethanes may offer strongerintermolecular forces than other amorphous components, such as diesters,for providing an ink capable of a more robust image.

Several suitable diurethanes were prepared by using a variety ofalcohols and diisocyanates as shown in Tables 1 and 2.

TABLE 1 Alcohol # Structure Name 1

Benzhydrol 2

Abitol E

TABLE 2 Diisocyanate # Structure Name 1

1,6-hexamethylen- diisocyanate (HDI) 2

Dicyclohexyl-methane diisocyanate (H12MDI) 3

2,4,4-trimethylhexa- methylenediisocyanate (TMHDI) 4

m-tetramethylxylylene diisocyanate (TMXDI) 5

1,3-bis(iisocyanato- methyl)cyclohexane (BIMC) 6

Isophoronoe diisocyanate (IPDI)

Typically, the amorphous material has a Tg range from about −20° C. toabout 50° C. Materials with a Tg below room temperature will be tacky orrunny materials that flow at room temperature. Conversely, materialswith a Tg above room temperature will be brittle and hard materials. Thegeneral trend is that the higher the Tg, the higher the viscosity of thematerial. While the structural activity relationships are not fullyunderstood, it is known that the Tg of isocyanate derived resins iscontrolled by the proper choice of alcohol and diisocyanate startingmaterials. Varying one or more of the alcohols and isocyanates willpermit custom tailoring of the Tg properties of the amorphous resinproduct.

The ink of embodiments may further include conventional additives totake advantage of the known functionality associated with suchconventional additives. Such additives may include, for example, atleast one antioxidant, defoamer, slip and leveling agents, clarifier,viscosity modifier, adhesive, plasticizer and the like.

The ink may optionally contain antioxidants to protect the images fromoxidation and also may protect the ink components from oxidation whileexisting as a heated melt in the ink reservoir. Examples of suitableantioxidants include N,N′-hexamethylene bis(3,5-di-tert-butyl-4-hydroxyhydrocinnamamide) (IRGANOX 1098, available from BASF),2,2-bis(4-(2-(3,5-di-tert-butyl-4-hydroxyhydrocinnamoyloxy))ethoxyphenyl)propane (TOPANOL-205, available from Vertellus),tris(4-tert-butyl-3-hydroxy-2,6-dimethyl benzyl)isocyanurate (Aldrich),2,2′-ethylidene bis(4,6-di-tert-butylphenyl)fluoro phosphonite(ETHANOX-398, available from Albermarle Corporation),tetrakis(2,4-di-tert-butylphenyl)-4,4′-biphenyl diphosphonite (ALDRICH46), pentaerythritol tetrastearate (TCI America), tributylammoniumhypophosphite (Aldrich), 2,6-di-tert-butyl-4-methoxyphenol (Aldrich),2,4-di-tert-butyl-6-(4-methoxybenzyl)phenol (Aldrich),4-bromo-2,6-dimethylphenol (Aldrich), 4-bromo-3,5-didimethylphenol(Aldrich), 4-bromo-2-nitrophenol (Aldrich), 4-(diethylaminomethyl)-2,5-dimethylphenol (Aldrich), 3-dimethylaminophenol(Aldrich), 2-amino-4-tert-amylphenol (Aldrich),2,6-bis(hydroxymethyl)-p-cresol (Aldrich), 2,2′-methylenediphenol(Aldrich), 5-(diethylamino)-2-nitrosophenol (Aldrich),2,6-dichloro-4-fluorophenol (Aldrich), 2,6-dibromo fluoro phenol(Aldrich), α-trifluoro-o-cresol (Aldrich), 2-bromo-4-fluorophenol(Aldrich), 4-fluorophenol (Aldrich),4-chlorophenyl-2-chloro-1,1,2-tri-fluoroethyl sulfone (Aldrich),3,4-difluoro phenylacetic acid (Adrich), 3-fluorophenylacetic acid(Aldrich), 3,5-difluoro phenylacetic acid (Aldrich),2-fluorophenylacetic acid (Aldrich), 2,5-bis (trifluoromethyl) benzoicacid (Aldrich),ethyl-2-(4-(4-(trifluoromethyl)phenoxy)phenoxy)propionate (Aldrich),tetrakis (2,4-di-tert-butyl phenyl)-4,4′-biphenyl diphosphonite(Aldrich), 4-tert-amyl phenol (Aldrich),3-(2H-benzotriazol-2-yl)-4-hydroxy phenethylalcohol (Aldrich), NAUGARD76, NAUGARD 445, NAUGARD 512, AND NAUGARD 524 (manufactured by ChemturaCorporation), and the like, as well as mixtures thereof. Theantioxidant, when present, may be present in the ink in any desired oreffective amount, such as from about 0.25 percent to about 10 percent byweight of the ink or from about 1 percent to about 5 percent by weightof the ink.

In embodiments, the phase change ink compositions described herein mayalso include a colorant. Any desired or effective colorant can beemployed in the phase change ink compositions, including dyes, pigments,mixtures thereof, and the like, provided that the colorant can bedissolved or dispersed in the ink carrier. Any dye or pigment may bechosen, provided that it is capable of being dispersed or dissolved inthe ink carrier and is compatible with the other ink components. Thephase change carrier compositions can be used in combination withconventional phase change ink colorant materials, such as Color Index(C.I.) Solvent Dyes, Disperse Dyes, modified Acid and Direct Dyes, BasicDyes, Sulphur Dyes, Vat Dyes, and the like. Examples of suitable dyesinclude Neozapon Red 492 (BASF); Orasol Red G (Pylam Products); DirectBrilliant Pink B (Oriental Giant Dyes); Direct Red 3BL (C₁₋assicDyestuffs); Supranol Brilliant Red 3BW (Bayer AG); Lemon Yellow 6G(United Chemie); Light Fast Yellow 3G (Shaanxi); Aizen Spilon YellowC-GNH (Hodogaya Chemical); Bemachrome Yellow GD Sub (Classic Dyestuffs);Cartasol Brilliant Yellow 4GF (Clariant); Cibanone Yellow 2G (ClassicDyestuffs); Orasol Black RLI (BASF); Orasol Black CN (Pylam Products);Savinyl Black RLSN(Clariant); Pyrazol Black BG (Clariant); Morfast Black101 (Rohm & Haas); Diaazol Black RN (ICI); Thermoplast Blue 670 (BASF);Orasol Blue GN (Pylam Products); Savinyl Blue GLS (Clariant); Luxol FastBlue MBSN (Pylam Products); Sevron Blue 5GMF (Classic Dyestuffs);Basacid Blue 750 (BASF); Keyplast Blue (Keystone Aniline Corporation);Neozapon Black X51 (BASF); Classic Solvent Black 7 (Classic Dyestuffs);Sudan Blue 670 (C.I. 61554) (BASF); Sudan Yellow 146 (C.I. 12700)(BASF); Sudan Red 462 (C.I. 26050) (BASF); C.I. Disperse Yellow 238;Neptune Red Base NB543 (BASF, C.I. Solvent Red 49); Neopen Blue FF-4012(BASF); Lampronol Black BR(C.I. Solvent Black 35) (ICI); Morton MorplasMagenta 36 (C.I. Solvent Red 172); metal phthalocyanine colorants suchas those disclosed in U.S. Pat. No. 6,221,137, the disclosure of whichis totally incorporated herein by reference, and the like. Polymericdyes can also be used, such as those disclosed in, for example, U.S.Pat. No. 5,621,022 and U.S. Pat. No. 5,231,135, the disclosures of eachof which are herein entirely incorporated herein by reference, andcommercially available from, for example, Milliken & Company as MillikenInk Yellow 869, Milliken Ink Blue 92, Milliken Ink Red 357, Milliken InkYellow 1800, Milliken Ink Black 8915-67, uncut Reactint Orange X-38,uncut Reactint Blue X-17, Solvent Yellow 162, Acid Red 52, Solvent Blue44, and uncut Reactint Violet X-80.

Pigments are also suitable colorants for the phase change inks. Examplesof suitable pigments include PALIOGEN Violet 5100 (BASF); PALIOGENViolet 5890 (BASF); HELIOGEN Green L8730 (BASF); LITHOL Scarlet D3700(BASF); SUNFAST Blue 15:4 (Sun Chemical); Hostaperm Blue B2G-D(Clariant); Hostaperm Blue B4G (Clariant); Permanent Red P-F7RK;Hostaperm Violet BL (Clariant); LITHOL Scarlet 4440 (BASF); Bon Red C(Dominion Color Company); ORACET Pink RF (BASF); PALIOGEN Red 3871K(BASF); SUNFAST Blue 15:3 (Sun Chemical); PALIOGEN Red 3340 (BASF);SUNFAST Carbazole Violet 23 (Sun Chemical); LITHOL Fast Scarlet L4300(BASF); SUNBRITE Yellow 17 (Sun Chemical); HELIOGEN Blue L6900, L7020(BASF); SUNBRITE Yellow 74 (Sun Chemical); SPECTRA PAC C Orange 16 (SunChemical); HELIOGEN Blue K6902, K6910 (BASF); SUNFAST Magenta 122 (SunChemical); HELIOGEN Blue D6840, D7080 (BASF); Sudan Blue OS (BASF);NEOPEN Blue FF4012 (BASF); PV Fast Blue B2GO1 (Clariant); IRGALITE BlueGLO (BASF); PALIOGEN Blue 6470 (BASF); Sudan Orange G (Aldrich), SudanOrange 220 (BASF); PALIOGEN Orange 3040 (BASF); PALIOGEN Yellow 152,1560 (BASF); LITHOL Fast Yellow 0991K (BASF); PALIOTOL Yellow 1840(BASF); NOVOPERM Yellow FGL (Clariant); Ink Jet Yellow 4G VP2532(Clariant); Toner Yellow HG (Clariant); Lumogen Yellow D0790 (BASF);Suco-Yellow L1250 (BASF); Suco-Yellow D1355 (BASF); Suco Fast YellowD1355, D1351 (BASF); HOSTAPERM Pink E 02 (Clariant); Hansa BrilliantYellow 5GX03 (Clariant); Permanent Yellow GRL 02 (Clariant); PermanentRubine L6B 05 (Clariant); FANAL Pink D4830 (BASF); CINQUASIA Magenta (DUPONT); PALIOGEN Black L0084 (BASF); Pigment Black K801 (BASF); andcarbon blacks such as REGAL 330™ (Cabot), Nipex 150 (Evonik) CarbonBlack 5250 and Carbon Black 5750 (Columbia Chemical), and the like, aswell as mixtures thereof.

Pigment dispersions in the ink base may be stabilized by synergists anddispersants. Generally, suitable pigments may be organic materials orinorganic.

Also suitable are the colorants disclosed in U.S. Pat. No. 6,472,523,U.S. Pat. No. 6,726,755, U.S. Pat. No. 6,476,219, U.S. Pat. No.6,576,747, U.S. Pat. No. 6,713,614, U.S. Pat. No. 6,663,703, U.S. Pat.No. 6,755,902, U.S. Pat. No. 6,590,082, U.S. Pat. No. 6,696,552, U.S.Pat. No. 6,576,748, U.S. Pat. No. 6,646,111, U.S. Pat. No. 6,673,139,U.S. Pat. No. 6,958,406, U.S. Pat. No. 6,821,327, U.S. Pat. No.7,053,227, U.S. Pat. No. 7,381,831 and U.S. Pat. No. 7,427,323, thedisclosures of each of which are incorporated herein by reference intheir entirety.

In embodiments, solvent dyes are employed. An example of a solvent dyesuitable for use herein may include spirit soluble dyes because of theircompatibility with the ink carriers disclosed herein. Examples ofsuitable spirit solvent dyes include Neozapon Red 492 (BASF); Orasol RedG (Pylam Products); Direct Brilliant Pink B (Global Colors); AizenSpilon Red C-BH (Hodogaya Chemical); Kayanol Red 3BL (Nippon Kayaku);Spirit Fast Yellow 3G; Aizen Spilon Yellow C-GNH (Hodogaya Chemical);Cartasol Brilliant Yellow 4GF (Clariant); Pergasol Yellow 5RA EX(Classic Dyestuffs); Orasol Black RLI (BASF); Savinyl Black RLS(Clariant); Morfast Black 101 (Rohm and Haas); Orasol Blue GN (PylamProducts); Thermoplast Blue 670 (BASF); Savinyl Blue GLS (Sandoz); LuxolFast Blue MBSN (Pylam); Sevron Blue 5GMF (Classic Dyestuffs); BasacidBlue 750 (BASF); Keyplast Blue E (Keystone Aniline Corporation);Neozapon Black X51 (C.I. Solvent Black, C.I. 12195) (BASF); Sudan Blue670 (C.I. 61554) (BASF); Sudan Yellow 146 (C.I. 12700) (BASF); Sudan Red462 (C.I. 260501) (BASF), mixtures thereof and the like.

The colorant may be present in the phase change ink in any desired oreffective amount to obtain the desired color or hue such as, forexample, at least from about 0.1 percent by weight of the ink to about50 percent by weight of the ink, at least from about 0.2 percent byweight of the ink to about 20 percent by weight of the ink, and at leastfrom about 0.5 percent by weight of the ink to about 10 percent byweight of the ink.

In embodiments, in the molten state, the ink carriers for the phasechange inks may have a viscosity of from about 1 to about 22 cps, orfrom about 4 to about 15 cps, or from about 6 to about 12 cps, at a thejetting temperature. The jetting temperature is typically comprised in arange from about 100° C. to about 140° C. In embodiments, the solid inkhas a viscosity of about >10⁶ cps, at room temperature. In embodiments,the solid ink has a T_(melt) of from about 65 to about 140° C., or fromabout 70 to about 140° C., from about 80 to about 135° C. and a T_(crys)of from about 40 to about 140° C., or from about 45 to about 130° C.,from about 50 to about 120° C., as determined by DSC at a rate of 10°C./min.

The ink compositions can be prepared by any desired or suitable method.For example, each of the components of the ink carrier can be mixedtogether, followed by heating, the mixture to at least its meltingpoint, for example from about 60° C. to about 150° C., 80° C. to about145° C. and 85° C. to about 140° C. The colorant may be added before theink ingredients have been heated or after the ink ingredients have beenheated. When pigments are the selected colorants, the molten mixture maybe subjected to grinding in an attritor or ball mill apparatus or otherhigh energy mixing equipment to affect dispersion of the pigment in theink carrier. The heated mixture is then stirred for about 5 seconds toabout 30 minutes or more, to obtain a substantially homogeneous, uniformmelt, followed by cooling the ink to ambient temperature (typically fromabout 20° C. to about 25° C.). The inks are solid at ambienttemperature. In a specific embodiment, during the formation process, theinks in their molten state are poured into molds and then allowed tocool and solidify to form ink sticks. Suitable ink preparationtechniques are disclosed in U.S. Pat. No. 7,186,762, the disclosure ofwhich is incorporated herein by reference in its entirety.

The inks can be employed in apparatus for direct printing ink jetprocesses and in indirect (offset) printing ink jet applications.Another embodiment disclosed herein is directed to a process whichcomprises incorporating an ink as disclosed herein into an ink jetprinting apparatus, melting the ink, and causing droplets of the meltedink to be ejected in an imagewise pattern onto a recording substrate. Adirect printing process is also disclosed in, for example, U.S. Pat. No.5,195,430, the disclosure of which is totally incorporated herein byreference. Yet another embodiment disclosed herein is directed to aprocess which comprises incorporating an ink as disclosed herein into anink jet printing apparatus, melting the ink, causing droplets of themelted ink to be ejected in an imagewise pattern onto an intermediatetransfer member, and transferring the ink in the imagewise pattern fromthe intermediate transfer member to a final recording substrate. In aspecific embodiment, the intermediate transfer member is heated to atemperature above that of the final recording sheet and below that ofthe melted ink in the printing apparatus. In another specificembodiment, both the intermediate transfer member and the finalrecording sheet are heated; in this embodiment, both the intermediatetransfer member and the final recording sheet are heated to atemperature below that of the melted ink in the printing apparatus; inthis embodiment, the relative temperatures of the intermediate transfermember and the final recording sheet can be (1) the intermediatetransfer member is heated to a temperature above that of the finalrecording substrate and below that of the melted ink in the printingapparatus; (2) the final recording substrate is heated to a temperatureabove that of the intermediate transfer member and below that of themelted ink in the printing apparatus; or (3) the intermediate transfermember and the final recording sheet are heated to approximately thesame temperature. An offset or indirect printing process is alsodisclosed in, for example, U.S. Pat. No. 5,389,958, the disclosure ofwhich is totally incorporated herein by reference. In one specificembodiment, the printing apparatus employs a piezoelectric printingprocess wherein droplets of the ink are caused to be ejected inimagewise pattern by oscillations of piezoelectric vibrating elements.Inks as disclosed herein can also be employed in other hot melt printingprocesses, such as hot melt acoustic ink jet printing, hot melt thermalink jet printing, hot melt continuous stream or deflection ink jetprinting, and the like. Phase change inks as disclosed herein can alsobe used in printing processes other than hot melt ink jet printingprocesses.

Such robust inks may be used with printing equipment at high speeds.Typically, production digital presses print at a speed comprised fromabout 100 to 500 or more feet/minute. This requires inks which arecapable of solidifying very fast once placed onto the paper, in order toprevent offset of the printed image during fast printing process, whereprinted paper is either stacked (cut-sheet printers) or rolled(continuous feed printers). Fast crystallization is not a general orinherent property of crystalline-amorphous robust inks. Therefore notall crystalline-amorphous inks are suitable for fast printing. Thepresent inventors have discovered specific crystalline amide compoundswhich when used in conjunction with specific amorphous compounds providefast crystallization, therefore enabling fast printing.

In order to evaluate the suitability of a test ink for fast printing aquantitative method for measuring the rates of crystallization of solidinks containing crystalline components was developed. TROM(Time-Resolved Optical Microscopy) enables comparison between varioustest samples and, as a result, is a useful tool for monitoring theprogress made with respect to the design of fast crystallizing inks.

TROM is described in co-pending U.S. patent application Ser. No. ______(not yet assigned) entitled “TROM Process for Measuring the Rate ofCrystallization of Solid Inks” to Gabriel Mime et al., electronicallyfiled on the same day herewith (Attorney Docket No. 20110828-401275),

Time Resolved Optical Microscopy (TROM) monitors the appearance and thegrowth of crystals by using Polarized Optical Microscopy (POM). Thesample is placed between crossed polarizers of the microscope.Crystalline materials are visible because they are birefringent.Amorphous materials or liquids, similar to, for example, inks in theirmolten state that do not transmit light, appear black under POM. Thus,POM enables an image contrast when viewing crystalline components andallows for pursuing crystallization kinetics of crystalline-amorphousinks when cooled from the molten state to a set-temperature. Polarizedoptical microscopy (POM) enables exceptional image contrast when viewingcrystalline components.

In order to obtain data that allow comparison between different andvarious samples, standardized TROM experimental conditions were set,with the goal of including as many parameters relevant to the actualprinting process. The ink or ink base is sandwiched between 16-25 mmcircular thin glass slides of a thickness of 0.2 mm to 0.5 mm. Thethickness of the ink layer is kept at 5-25 μm (controlled withfiberglass spacers) which is close to actual printed ink layers. Forrate of crystallization measurement, the sample is heated to theexpected jetting temperature (viscosity of about 10-12 cps) via anoffline hotplate and then transferred to a cooling stage coupled with anoptical microscope. The cooling stage is thermostated at a presettemperature which is maintained by controlled supply of heat and liquidnitrogen. This experimental set-up models the expected drum/papertemperature onto which a drop of ink would be jetted in real printingprocess (40° C. for the experiments reported in this disclosure).Crystal formation and growth is recorded with a camera.

The key steps in the TROM process are illustrated in FIG. 1,highlighting the key steps in the measuring process with the mainlineink base which contains just amorphous and crystalline components (nodye or pigment). When viewed under POM, the molten and at time zero, thecrystalline-amorphous inks appear black as no light is passed through.As the sample crystallizes, the crystalline areas appear brighter. Thenumbers reported by

TROM include: the time from the first crystal (crystallization onset) tothe last (crystallization completion).

The definition of key measured parameters of the TROM process are setforth below:

-   -   Time zero (T=0 s)—the molten sample is placed on the cooling        stage under microscope    -   T onset=the time when the first crystal appears    -   T growth=the duration of the crystal growth from the first        crystal (T onset) to the completion of the crystallization (T        total)    -   T total=T onset+T growth

It should be understood that the crystallization times obtained with theTROM method for selected inks are not identical to what would be thecrystallization times of a droplet of ink in an actual printing device.In an actual printing device such as a printer, the ink solidifies muchfaster. We determined that there is a good correlation between the totalcrystallization time as measured by the TROM method and thesolidification time of an ink in a printer. In the standardizedconditions described above, we determined that inks solidify within10-15 seconds or less measured by the TROM method, are suitable for fastprinting, typically at speeds from 100 feet/minute or higher. Therefore,for the purpose of the present disclosure, a rate of crystallizationlower than 15 seconds, are considered to be fast crystallizing.

In certain embodiments, the phase change ink crystallizes in less than15 seconds.

Any suitable substrate or recording sheet can be employed, includingplain papers such as XEROX 4200 papers, XEROX Image Series papers,Courtland 4024 DP paper, ruled notebook paper, bond paper, silica coatedpapers such as Sharp Company silica coated paper, JuJo paper, HAMMERMILLLASERPRINT paper, and the like, glossy coated papers such as XEROXDigital Color Elite Gloss, Sappi Warren Papers LUSTROGLOSS, specialtypapers such as Xerox DURAPAPER, and the like, transparency materials,fabrics, textile products, plastics, polymeric films, inorganicrecording mediums such as metals and wood, and the like, transparencymaterials, fabrics, textile products, plastics, polymeric films,inorganic substrates such as metals and wood, and the like.

The inks described herein are further illustrated in the followingexamples. All parts and percentages are by weight unless otherwiseindicated.

It will be appreciated that various of the above-disclosed and otherfeatures and functions, or alternatives thereof, may be desirablycombined into many other different systems or applications. Also,various presently unforeseen or unanticipated alternatives,modifications, variations or improvements therein may be subsequentlymade by those skilled in the art, and are also intended to beencompassed by the following claims.

While the description above refers to particular embodiments, it will beunderstood that many modifications may be made without departing fromthe spirit thereof. The accompanying claims are intended to cover suchmodifications as would fall within the true scope and spirit ofembodiments herein.

The presently disclosed embodiments are, therefore, to be considered inall respects as illustrative and not restrictive, the scope ofembodiments being indicated by the appended claims rather than theforegoing description. All changes that come within the meaning of andrange of equivalency of the claims are intended to be embraced therein.

EXAMPLES

The examples set forth herein below and are illustrative of differentcompositions and conditions that can be used in practicing the presentembodiments. All proportions are by weight unless otherwise indicated.It will be apparent, however, that the present embodiments can bepracticed with many types of compositions and can have many differentuses in accordance with the disclosure above and as pointed outhereinafter.

Example 1 Synthesis of Diurethane Compound 1 from HDI and Abitol E

A 250 mL vessel equipped with a stir magnet was charged 50.3 g Abitol E(available from Eastman Corporation) (4.8% OH content, calculated Mw=354g/mol, 339 mmol) and 1 drop Fascat 4202 catalyst. The jar was placed inan about 130° C. oil bath. 11.4 g HDI (MW=168 g/mol, 169 mmol) was thenadded. An exotherm was observed. Infrared (IR) was checked after 1 hr ofreaction. The IR showed no isocyanate peak at ca. 2265 cm⁻¹, indicatingthat the reaction was complete. The reaction contents were poured into atin pan to cool and solidify as a glassy amorphous solid.

Example 2 Synthesis of Diurethane Compound 2 from BIMC and Benzhydrol

A 100 mL vessel equipped with a stir magnet was charged 9 g benzhydrol(available from Aldrich) (Mw=184 g/mol, 652 mmol) and 1 drop of Fascat4202 catalyst. The jar was placed in an about 130° C. oil bath. 4.7 gBIMC (Mw=194 g/mol, 326 mmol) was then added. An exotherm was observed.IR was checked after 1 hr of reaction. The IR showed no isocyanate peakat ca. 2265 cm⁻¹, indicating that the reaction was complete. Thereaction contents were poured into a tin pan to cool and solidify as aglassy amorphous solid.

Example 3 Synthesis of Diurethane Compound 3 from TMXDI and BenzylAlcohol

A 100 mL vessel equipped with a stir magnet was charged 13.0 g benzylalcohol (available from Aldrich) (Mw=108 g/mol, 1.111 mmol) and 1 dropof Fascat 4202 catalyst. The jar was placed in an about 130° C. oilbath. 14.6 g TMXDI (Mw=244 g/mol, 555 mmol) was then added. An exothermwas observed. IR was checked after 1 hr of reaction. The IR of a samplefrom the reaction mixture showed an isocyanate peak so an additional 0.5grams of benzyl alcohol were added and allowed to react for 30 minutes.The IR of a sample from the reaction mixture still showed an isocyanatepeak so an additional 1.0 grams of benzyl alcohol were added and allowedto react for an additional 30 minutes. The IR of a sample from thereaction mixture showed no isocyanate peak at ca. 2265 cm⁻¹ indicatingthat the reaction was complete. The reaction contents were poured into atin pan to cool and solidify as an amorphous solid.

Characterization of Amorphous Diurethane Compound 1 and Inks Containingthe Same

As shown in FIG. 2, Diurethane Compound 1 was characterized bymeasurement of the T_(g) (glass transition temperature) using a DSCtechnique on a TA instruments DSC Q1000 with a rate of heating/coolingof 10° C./min. Table 3 summarizes the T_(g) data for DiurethaneCompounds 1, 2, and 3. As can be seen, the data in Table 3 furthersupports the utility of these materials as amorphous resins.

TABLE 3 Diurethane Compound Tg/° C. 1. (Abitol)₂-HDI 17.9 2.(benzhydrol)₂-BIMC 15.82 3. (benzyl)₂-TMXDI 0.41

The rheology of Diurethane Compound 1 was also measured, and shown inFIG. 3, using an RFS3 controlled strain Rheometer (TA instruments)equipped with a Peltier heating plate and using a 25 mm parallel plate.The method used was a temperature sweep from high to low temperatures,in temperature steps of 5° C., a soak (equilibration) time of 120seconds between each temperature and at a constant frequency of 1 Hz.

One sample ink was prepared containing an 80:20 blend of a crystallinediurethane compound, dibenzyl hexane-1,6-diyldicarbamate, previouslydisclosed in U.S. patent application Ser. No. ______ to Chopra et al.(Attorney Docket No. 20110356-396152), entitled “Phase Change InkCompositions Comprising Diurethanes and Derivatives Thereof,” andamorphous Diurethane Compound 1. The ink formulation is shown in Table4.

TABLE 4 Component Wt % Mass/g dibenzyl hexane-1,6- 78.4 3.92diyldicarbamate (Abitol)₂HDI diurethane 19.6 0.98 Solvent Blue 101(Keyplast Blue E) 2.0 0.1 TOTAL 100% 5.0 g

To prepare the sample ink, crystalline and amorphous resins and dye wereadded to a 25 mL bottle with a stir bar. The mixture was heated to 140°C. in a heating block with stirring for 1 hour, then the molten mixturewas poured into a foil pan to cool and solidify.

Ink Characterization

The rheology of the Ink was measured, as shown in FIG. 4, using an RFS3controlled strain Rheometer (TA instruments) equipped with a Peltierheating plate and using a 25 mm parallel plate.

Comparative data for this ink and two commercially available inks wereobtained for crystallization and are shown in Table 6 below. Rate ofcrystallization was measured by Time-Resolved Optical Microscopy (TROM)procedure.

TROM results are shown in Table 5 for a fast ink (Commercial Ink A), fora slow ink (Commercial Ink B) and for the ink described in Table 4. Thisexample demonstrates that fast crystallizing inks can be designed byusing amorphous diurethane components. Fast crystallization ofcrystalline-amorphous inks containing amorphous diurethanes is notnecessarily an inherent property of the amorphous urethane. Ultimatelythe rate of crystallization will depend on the selection of the pair ofamorphous and crystalline components. In this way it is possible to tunethe rate of crystallization of such inks within desired ranges betweenslow and fast crystallization rates. Both fast and slow inks may bedesired since each has benefits. Fast crystallizing inks enable highspeed printing. One potential benefit of slower crystallizing inks maybe deeper penetration into the paper which may provide improved imagerobustness.

TABLE 5 T T T Test onset grow total Ink Temp. (sec) (sec) (sec)Commercial Ink A 110 2 2 4 Commercial Ink B 120 7 29 36 Ink withamorphous 120 2 6 8 diurethane disclosed here

Correlation experiments conducted with a web-fed printer have shown thatan ink which shows a total crystallization time of about 4 seconds likeCommercial Ink A is suitable for printing at fast speed, while an inkwhich in TROM procedure takes about over 20 seconds is too slow to allowfast printing rate as required by next generation printers. Inks with acrystallization time close to 15 seconds or less are expected to besuitable for fast printing. As seen from the data presented, one of thebenefits of the present embodiments is that there is provided a robustink which also is a fast printing ink. Neither of the two comparativecommercial inks meets both requirements. For example, Commercial Ink Aprovides fast print but poor robustness while Commercial Ink B providesgood robustness but with slow printing.

Robustness Performance

Image samples created by the phase change ink composition on coatedpaper by K-proof exhibit excellent robustness. As stated above, aK-proofer is a common test fixture in a print shop. In this case theproofer has been modified to heat the printing plate to melt the phasechange ink. The K-Proofer used has three rectangular gravure patternseach approximately 9.4×4.7 cm. The cell density of the first rectangleis nominally 100%, the second 80%, and the third 60%. In practice thisK-proof plate results in films (or pixels) of about 5 microns inthickness (or height). Test ink is spread over the heated gravure plateand a test print is made by passing a wiping blade across the platesurface immediately follow by a rubber roll upon which a test paper hasbeen secured. As the paper roll passes ink is transferred from thegravure cells to the paper.

K-proof analyses showed superior scratch resistance of Ink when comparedto commercially available inks, such as Commercial Ink A and CommercialInk B, and comparable fold crease and fold offset when compared to thesame commercially available inks.

In summary, the present embodiments provide robust phase change inkformulations developed for inkjet printing which contains at least onecrystalline material and at least one amorphous material. The inks mayalso include a colorant, such as a pigment or dye. The amorphousmaterials are selected diurethane compounds which have demonstrated tohave suitable properties for use as the amorphous component in phasechange ink compositions and are miscible with the crystalline materials.The amorphous materials have desirable physical properties which providefor inks having improved robustness against scratch, fold offset andfold crease as compared to other commercially available phase changeinks.

The claims, as originally presented and as they may be amended,encompass variations, alternatives, modifications, improvements,equivalents, and substantial equivalents of the embodiments andteachings disclosed herein, including those that are presentlyunforeseen or unappreciated, and that, for example, may arise fromapplicants/patentees and others. Unless specifically recited in a claim,steps or components of claims should not be implied or imported from thespecification or any other claims as to any particular order, number,position, size, shape, angle, color, or material.

All the patents and applications referred to herein are herebyspecifically, and totally incorporated herein by reference in theirentirety in the instant specification.

1. A phase change ink comprising: a crystalline compound having aformula of:

wherein Q is alkanediyl; each R₆ and R₇ is independently phenyl orcyclohexyl optionally substituted with one or more alkyl; i is 0 or 1; jis 0 or 1; p is 1 to 4; q is 1 to 4, further wherein the crystallinecompound is present in an amount of from 60 percent to 95 percent byweight of the total weight of the phase change ink; and an amorphousdiurethane compound having a formula of:

wherein Z is selected from the group consisting of

wherein each R₃ and R₄ is i) an alkyl group wherein the alkyl can belinear or branched having from about 1 to about 8 carbon atoms, or ii)an aryl group; with the proviso that when Z is —(CH₂)₆—, both R₃ and R₄are not —(CH₂)₆—C₆H₅ wherein n=0-4; wherein the amorphous diurethanecompound is present in an amount of from 5 percent to 40 percent byweight of the total weight of the phase change ink; wherein the phasechange ink crystallizes in less than 15 seconds.
 2. The phase change inkof claim 1, wherein each R₃ and R₄ is independently selected from thegroup consisting of

with the proviso that when Z is —(CH₂)₆—, both R₃ and R₄ are not—(CH₂)₆—C₆H₅ wherein n=0-4.
 3. The phase change ink of claim 1, whereinthe amorphous diurethane compound is selected from the group consistingof

and mixtures thereof.
 4. (canceled)
 5. (canceled)
 6. The phase changeink of claim 1 further comprising a colorant selected from the groupconsisting of a pigment, dye, and mixtures thereof.
 7. The phase changeink of claim 1, wherein the crystalline/amorphous ratio is from 60:40 to95:5.
 8. The phase change ink of claim 1, wherein the amorphous compoundhas a viscosity of less than 100 cps at a temperature of 140° C.
 9. Thephase change ink of claim 1, wherein the amorphous compound has aviscosity of greater than 1×10⁵ cps at room temperature.
 10. The phasechange ink of claim 1 having a viscosity of less than 15 cps in ajetting range of from about from 100° C. to 140° C.
 11. The phase changeink of claim 1 having a viscosity of greater than about 10⁶ cps at roomtemperature.
 12. A phase change ink comprising: an amorphous diurethanecompound; and a crystalline compound; wherein the amorphous diurethanecompound is synthesized from a diisocyanate and at least one alcoholoptionally in the presence of a catalyst.
 13. The phase change ink ofclaim 12, wherein the diisocyanate is selected from the group consistingof 1,6-hexamethylenediisocyanate, isophoronediisocyanate,1,3-bis(isocyanatomethyl)cyclohexane, m-tetramethyl xylylenediisocyanate, dicyclohexylmethane diisocyanate and2,4,4-trimethylhexamethylene diisocyanate,(hexamethylene-1,6-diisocyanate (HDI); trimethylhexamethylenediisocyanate (TMHDI); 2,5-bis-isocyanatomethylene diisocyanate (BIMC),tetramethylxylene diisocyanate (TMXDI); isophorone diisocyanate (IPDI),diphenylmethane-4,4′-diisocyanate (MDI); hydrogenateddiphenylmethane-4,4′-diisocyanate (H₁₂MDI); phenylisocyanate; toluenediisocyanate (TDI), phenylene diisocyanate, and mixtures thereof. 14.The phase change ink of claim 12, wherein the alcohol is selected fromthe group consisting of

and mixtures thereof with the proviso that when Z is —(CH₂)₆—, both R₃and R₄ are not —(CH₂)_(n)—C₆H₅ wherein n=0-4.
 15. The phase change inkof claim 12, wherein the catalyst is selected from the group consistingof a dibutyl tin dilaurate, dibutyl tin oxide, zinc catalyst and bismuthcatalyst, and mixtures thereof.
 16. The phase change ink of claim 12having a jetting range of from about from about 90 to about 150° C. 17.A phase change ink comprising: a crystalline compound having a formulaof:

wherein Q is alkanediyl; each R6 and R7 is independently phenyl orcyclohexyl optionally substituted with one or more alkyl; i is 0 or 1; jis 0 or 1; p is 1 to 4; q is 1 to 4, further wherein the crystallinecompound is present in an amount of from 60 percent to 95 percent byweight of the total weight of the phase change ink; an amorphousdiurethane compound having a formula of:

wherein Z is selected from the group consisting of

wherein each R₃ and R₄ is i) an alkyl group wherein the alkyl can belinear or branched having from about 1 to about 8 carbon atoms, or ii)an aryl group; each R₃ and R₄ is independently selected from the groupconsisting of

with the proviso that when Z is —(CH₂)₆—, both R₃ and R₄ are not—(CH₂)₆—C₆H₅ wherein n=0-4; wherein the amorphous diurethane compound ispresent in an amount of from 5 percent to 40 percent by weight of thetotal weight of the phase change ink.
 18. The phase change ink of claim17, wherein the amorphous compound is present in an amount of from 5percent to 40 percent by weight of the total weight of the phase changeink.
 19. (canceled)
 20. The ink in claim 17, wherein the phase changeink crystallizes in less than 15 seconds.